Around the country, natural gas is slowly but surely becoming the fuel of choice. The production of enormous amounts of shale gas in Ohio, Pennsylvania and other states is benefiting consumers, creating thousands of jobs, revitalizing the manufacturing sector, and generating billions of dollars in revenue.
But critics of hydraulic fracturing, or "fracing" - the process used to stimulate gas production from conventional oil and gas reservoirs as well as the Utica and Marcellus shales and other shale formations - claim that it is hazardous. One of the arguments is that the disposal of fracing fluid in injection wells has triggered earthquakes, and that more earthquakes can be expected in the future.
Fracing has enormous economic and environmental benefits when employed to increase natural gas production. It is being done safely and responsibly, but no one, other than those employing it, seems to know it. Without access to shale gas, we would be importing large quantities of gas from Canada and Mexico as well as liquefied natural gas (LNG) from other countries overseas. Instead, we are actually able to export some of our domestic gas, thus helping to reduce the U.S. trade deficit while bolstering domestic gas production and stimulating the U.S. economy.
But there is a kernel of truth to what opponents say about the disposal of wastewater in deep injection wells. If not done properly, the injection of huge amounts of wastewater can trigger tremors such as those that were felt in the Youngstown area earlier this year and in Arkansas, Texas and near the Colorado-New Mexico border. The link between wastewater injection and tremors in northeastern Ohio was confirmed recently by the Ohio Department of Natural Resources, which directed operators of injection wells to submit more comprehensive geological data when requesting permission to use a wastewater drill site, among other regulations.
The oil-and-gas industry needs to be out ahead of regulators if it hopes to head off potential problems. There are over 140,000 injection wells around the country, some used since the 1960s, but it's important to realize that only a handful of incidents have occurred. None of the tremors has caused any injury or serious damage. While there's no uniform answer for all injection wells, some changes can lessen the potential for trouble.
Technological improvements will be a big help. With more effective fracing that makes use of better data identifying which are the best zones in a shale formation to penetrate, as much as a 50 percent reduction in water usage may be possible. In other words, companies are developing ways to produce more gas with less frac fluid. And some companies already are recycling 100 percent of their fracing fluid, significantly reducing the amount of wastewater requiring disposal in an injection well.
As Fred Krupp, president of the Environmental Defense Fund, said at a recent energy conference in Houston: "There are smart, common sense steps being taken to prevent earthquakes."
In addition to recycling wastewater, some additional measures can be taken immediately. Producers need to avoid injecting wastewater into active faults. They also need to reduce injection pressure at deep depths. And they need better information about how much fluid is being injected into each and every disposal well.
Perhaps most importantly, we need a network of seismic monitors near injection wells - a stoplight system. With such a system, it would be possible to detect seismicity in real time, thereby preventing serious problems from happening. The cost of such a seismic network would not be unreasonable - about $100,000 to install and a few thousand dollars annually to maintain.
Finally, it's essential that all shale-gas producers adhere to the best performance practices recommended by the Department of Energy's shale-gas committee, because an accident anywhere is an accident everywhere. Each company has a vested interest in getting the job done right. Each must do everything to ensure public trust.
Dr. Robert W. Chase is chair and professor of the Department of Petroleum Engineering and Geology at Marietta College.
